What causes thick hard skin?
When walking or running, or even just when standing still, the feet need to carry and support the entire bodyweight and with every step the feet are pressed and squashed and rubbed. This means that the skin on the feet have to cope with a lot of pressure and friction. If the amount of pressure and friction is increased over a period of time the body will react by adding extra layers of skin for protection. (If there is a lot of intense friction over a short period of time the body might develop a blister – see blisters for more information.)
These extra layers of skin build up as they are not as easily shed as normal skin (which is lost from the skin surface every day), and form an area of thick hard skin.
This thick hard skin is often found on the ball of foot, the heel and the toes as these are the areas that experience the most pressure and friction.